Activity trackers: game changers or bathroom scales for the 21st century?

After millions of dollars of investment and hundreds of thousands of hours of work by code-writers and engineers, it looks as if we might have re-invented the bathroom scales.

Admittedly, what we have now is shinier, hi-tech, and more portable. But also more expensive than traditional bathroom scales.

Personal activity trackers such as Fitbit, Apple Watch and others are much-loved by fitness-oriented 20-35 year-olds, helping them keep track of their personal best runs, cycle-rides, steps or whatever.

Silicon Valley and the world of tech loves to promote itself as “game-changing” and making the world a better place in which technology is “the answer” to whatever problems we messy humans have. But the great hope that trackers could help fight the overweight crisis is beginning to look over-blown.

The unthinking naivety of the tech world was neatly summarized by a professor of preventative medicine at the Pennington Biomedical Research Centre, who was quoted in USA Today as saying: “If you put a scale in someone’s bathroom, that doesn’t mean they are going to lose weight. The tracker is not going to tie your running shoes and move your feet.”

The evidence? A study published in the medical journal The Lancet Diabetes & Endocrinology1 investigated the extent which an activity tracker – with or without cash incentives – could increase physical activity and improve health outcomes among working people during a 6-month period.

Employees from 13 organizations in Singapore were randomized into 4 study groups, ranging from a control (with no tracker) to a group that was given a tracker plus cash payments if they logged more than 50,000 steps per week.

The result? No evidence of improved health outcomes because of the trackers. Within 6 months, 40% abandoned the Fitbit and by month 12 that number increased to 90%.

The researchers say that because there are beneficial effects among participants in the Fitbit group at month 12 (despite the lack of wear), it is possible that participants wore the unit for a brief period of time, learned about their activity patterns, and then stopped wearing it.

The cash incentive was most effective at increasing physical activity, but this effect stopped after the cash payments stopped.

Another study, published in the Journal of the American Medical Association2, investigated the effect of wearable technology on weight loss, body composition, fitness, physical activity, and dietary intake over 24 months among 470 adults aged 18-35.

The 470 participants were divided between a group that followed a conventional behavioral weight loss intervention and another that had the added advantage of wearable technology.

The result? Both groups had significant improvements in body composition, fitness, physical activity, and diet.

But the conventional weight-loss group had an average 5.9kg weight loss after 24 months in comparison to 3.5kg in the technology-enhanced group.

The PR engines of the tech companies behind the tracker market burst into life, with their own critique of the study results: “We would strongly caution against any conclusion that these findings apply to the wearable technology category as a whole.”

As health researchers, food companies, drug makers and doctors know very well, there’s no magic bullet when it comes to fighting overweight and obesity. It has to be tackled from many different angles. The tech industry has overlooked this complexity and may have over-promised in its excitement about its gadgets.

It’s people taking action that produces change. Technology is not “the answer”. Technology can at best be a handy tool to back up people’s own efforts – rather like a set of bathroom scales, perhaps.